Chaining mechanism for overedge sewing machine

ABSTRACT

An improved chaining mechanism for an overedge sewing machine having a pair of needles supported in alignment in the direction of feed of work material through the machine for simultaneously penetrating the workpiece at spaced points along the length of a seam formed by the machine. A pair of chaining fingers are provided in alignment in the direction of feed through the machine, and in laterally spaced relation to the needles so that independent stitches formed with respective threads carried by each of the needles may be formed around a separate chaining finger.

I Umted States Patent 1 1 3,590,757

[72] Inventor George B. ArmsteadJr. [56] References Cited 89 Harvest Lane, Glastonbury, Conn. UMTED STATES PATENTS 06033 l,305,05l 5/l9l9 Berger, Jr. 1l2/260 I 21l PP'- 35-649 3,079,882 3/1963 Washburn 112/260 {221 PM T 3;? 3.100.469 8/1963 Washburn 112/260 Paemed t f Se N 3192,1187 7/1965 Perl 1l2/l62 ;;"gf"";f: "1 "5 3,246,620 4/1966 Sigoda et al. ll2/l62 ,6 1 a 3,373,706 3/1968 Armstead,.lr. 112/162 Primary Examiner-James R. Boler AltomeyBeveridge & DeGrandi ABSTRACT: An improved chaining mechanism for an overedge sewing machine having a pair of needles supported [54] CHMNING MECHANISM FOR OVEREDGE in alignment in the direction of feed of work material through SEWWG the machine for simultaneously penetrating the workpiece at Clams 12 Drawmg spaced points along the length of a seam formed by the [52] US. Cl 112/162, machine. A pair of chaining fingers are provided in alignment 1 12/235, 1 12/260 in the direction of feed through the machine, and in laterally [51] lnt.Cl D05h l/20 spaced relation to the needles so that independent stitches [50] Field of Search l 12/ 162, formed with respective threads carried by each of the needles may be formed around a separate chaining finger.

PATENIED JUL 6 IH'II SHEET 1 0F 4 FIG. I

INVENTOR GEORGE B. ARMSTEAD JR.

BY flaming 'ZiV/ ATTOR NEYS.

PATENTED JUL 6 I971 SHEEI 2 OF 4 FIG. 3

FIG. 5

FIG. 6

INVENTOR GEORGE B. ARMSTEAD, JR.

BY u i ATTORNEYS,

PATENTEIJJUL 6l97| 3,590,757

SHEET 3 BF 4 FIG. 7

FIG. 8

INVENTOR GEORGE B. ARMSTEAD, JR.

15. BY glow/7i A ATTORNEYS.

PATENTEUJUL 6IH7| 3590157 sum u 0F 4 FIG. IO

FIG. ll

FIG. l2

INVENTOR GEORGE B. ARMSTEAD, JR.

ATTORNEYS,

CHAINING MECHANISM FOR OVEREDGE SEWING MACHINE RELATED APPLICATIONS This is a continuation-in-part of my copending application Ser. No. 792,654, filed Jan. 21, I969, now abandoned.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to overedge sewing machines, and is particularly concerned with an improved chaining finger structure of the general type incorporated in overedge sewing machines.

2. Description of the Prior Art In the operation of conventional overedge sewing machines, it is a common practice to employ a chaining finger adjacent the edge of the material being sewn so that the individual stitches formed in the edge of the material are formed around the chaining finger, with the stitches being cast off the chaining finger as the sewn material passes through the machine. In certain of the known overedge sewing machines, such as the Merrow machine illustrated in US. Pat. No. 2,931,328, the complex movement of the needle and looper mechanism, which must be operated in synchronization with the needle, imposes practical limitations on the maximum speed at which the machine may be operated. In my US. Pat. No. 3,373,706, I have disclosed an overedge sewing machine of this general type which permits the formation of an overedge seam at substantially increased rates without requiring the stitch forming mechanism to be operated at excessive speeds. While the im proved machine shown in my earlier patent has been entirely satisfactory for many sewing operations, difficulty has been encountered in certain instances in producing comparable stitch formations with the two needles. This difficulty has resulted primarily from the fact that the two stitches were simultaneously cast around a single chaining finger structure which necessarily tapered toward the rear of the machine so that the cross-sectional area of the chaining finger at the rear needle was less than at the front needle, and the stitch formed by the front needle remained on the chaining finger longer than that formed by the rear needle.

Another difficulty which has been encountered in the operation of machines of the type illustrated in my earlier patent is that, in certain sewing operations, there is a tendency for the rear upper looper to impale the front needle thread, thereby causing skipping in both systems. This results from the fact that the needle threads are inclined to the rear of the machine when the needles are withdrawn. At the same time the anchored ends of the threads are shifted to the rear of the machine by the feed mechanism. When the needle spacing is small relative to the length of stitches formed by the individual needles, this may result in the forward needle thread being brought into the plane of motion of the rear looper.

SUMMARY OF THE INVENTION The foregoing and other objects of the prior art are overcome by the present invention by providing a separate chaining finger for the stitches formed by each of the two needles of a sewing machine of the type employing two separate needles supported in alignment with one another along the direction of feed of the workpiece through the machine. The two chaining fingers are supported in alignment with one another, one adjacent each of the needles, so that the looper mechanism of the machine, in cooperation with the needles, can simultaneously form two stitches, one around each of the chaining fingers. The two chaining fingers may be formed in the needle plate, or the presser foot, or one on each. An arm supported in the presser foot of the machine projects across the path of movement of thread from the front needle to act as a guard to prevent the rear looper from impaling the front needle thread.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects and advantages of the invention will become apparent from the following detailed description, taken with the drawings, in which:

FIG. I is a fragmentary, top plan view of an overedge sewing machine embodying the present invention;

FIG. 2 is a fragmentary end elevation view of the sewing machine illustrated in FIG. I, with certain parts omitted and other parts broken away;

FIG. 3 is a fragmentary top plan view of one configuration of the chaining finger structure of the machine shown in FIGS. 1 and 2',

FIG. 4 is an elevation view of the chaining structure shown in FIG. 3;

FIG. 5 is a fragmentary top plan view similar to FIG. 3 and illustrating an alternate embodiment of the chaining structure;

FIG. 6 is an elevation view ofthe structure shown in FIG. 5;

FIG. 7 is a view similar to FIG. 6, and showing the two needles penetrating a workpiece;

FIG. 8 is a view similar to FIG. 7, showing the needles being withdrawn;

FIG. 9 is a view similar to FIG. 7, showing the needles fully retracted and the workpiece shifted to the rear, and with certain parts shown in section;

FIG. 10 is a sectional view taken on line 10-10 of FIG. 9;

FIG. 11 is a top plan view similar to FIG. 3 and showing an alternate embodiment of the invention; and

FIG. 12 is a side elevation view of the structure shown in FIG. 11.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring now to the drawings in detail, an overedge sewing machine according to the present invention is indicated generally by the reference numeral 10 and includes a housing 12 containing the drive mechanism for a conventional fourmotion feed dog mechanism 14 for feeding a workpiece 15 (see FIGS. 79) over a support surface defined by a work support plate 16 and a needle plate 18 past the stitch forming mechanism of the sewing machine. The stitch forming mechanism includes a front needle 20 and a rear needle 21 mounted for reciprocating movement on a needle carriage 22, a pair of lower loopers 23, 24 mounted on a lower looper carrier 26, and a pair of upper loopers 27, 28 mounted on an upper looper carrier 30. The needles 20, 21 are supported in alignment along the direction of feed of work material through the machine, and the looper carriers 26, 30 are driven in coordination with one another and with the needle carrier 22 to simultaneously form a pair of stitches with threads 33, 31 carried by the respective needles 20, 21. Thus, since two stitches are simultaneously formed through the work material following each increment of feed, the completed seam may be formed at an increased rate as described in my earlier patent, mentioned above.

In order to assure that the stitches formed by the two needles are of comparable quality, an improved needle plate 18 and presser foot assembly 32 cooperate to provide a separate chaining finger adjacent the respective needles 20, 21 so that stitches formed by threads 33, 31 carried by the respective needles may be simultaneously formed around separate chaining finger structures. In one embodiment of the invention, illustrated in FIGS. 1, 3 and 4, the presser foot 32 is supported in the conventional manner for limited pivotal movement about a horizontal axis defined by a finger 34 on the end of a support arm 36 by a spring clip 38 mounted on the body of the presser foot 32 by a machine screw 40. A transversely extending keyway 42 is formed in the body of presser foot 32 forward of finger 34 for receiving a complementary key portion of a block 44, with the block 44 being retained on the presser foot 32 by the screw 40 extending therethrough. An arm 46 is integrally formed on and projects laterally from block 44 and supports an integrally formed chaining finger 48 extending rearwardly in laterally spaced relation to the side edge of presser foot 32 to define a needle opening or slot in the presser foot for the adjacent needle 20. Chaining finger 48 is tapered rearwardly from a maximum cross-sectional area at its forward end near the needle 20 and terminates in a rounded end spaced rearwardly from the needle 20. The taper of the chaining finger 48 is such that a stitch formed around the chaining finger will shed therefrom as a workpiece is fed through the machine.

A second chaining finger 50 is positioned in alignment with and to the rear of chaining finger 48, and extends toward the rear of the machine adjacent needle 21. Chaining finger 50 is supported at its forward end by an arm 52 extending transversely of presser foot 32 and projecting through an opening in a bracket 54 integrally formed on the upper surface of the presser foot 32. The end of arm 52 which projects through bracket 54 is threaded, and a nut 56 is mounted thereon to retain the arm and chaining finger in position. Thus, arm 52 and finger 50 cooperate to define a second needle opening in the presser foot for the second needle 21. Like chaining finger 48, chaining finger 50 has its maximum cross-sectional area at its forward end near needle 21, and tapers toward the rear of the machine to shed a stitch formed therearound in the conventional manner. As indicated in FIG. 4, the chaining fingers 48 and 50 have their forward faces inclined downwardly and to the rear of the machine to facilitate the passing of a work piece beneath the chaining fingers.

As best seen in FIGS. 3 and 4, the needle plate 111 includes a pair of stub fabric supporting fingers 60, 62, respectively, formed on the ends of laterally projecting arms 64, 66. The stub finger 60 underlies chaining finger 48 so that the edge of a piece of work material is supported therebetween as the needle 20 penetrates the material and as the looper mechanism forms the stitch over the edge of the material and around the chaining finger. Similarly, stub finger 62 is positioned beneath chaining finger 50 and supports the edge of the work material adjacent the needle 21. Fingers 60 and 62 extend slightly to the rear of needles 20, 21, respectively, so that the looper mechanism actually forms the stitches around the ends of these stub fingers and the adjacent chaining finger. However, fingers 60 and 62 are tapered relatively bluntly toward the rear of the machine so that stitches initially formed therearound are quickly shed therefrom.

' Referring now to FIGS. 5 and 6, an alternate embodiment of the invention will be described. In this embodiment, the presser foot assembly 32 is identical to that described above, with the single exception that the rear chaining finger 50 has been replaced with a stub fabric supporting finger 150. Similarly, the needle plate 18 is identical to that described above with the single exception that the rear stub finger 62 has been replaced with an elongated chaining finger 162. Thus, in the embodiment illustrated in FIG. 5, a stitch formed from a thread carried by the forward needle 20 is formed around a stub finger 60 on the needle plate 18 and a chaining finger 48 on the presser foot 32 while a stitch formed by thread carried by the rear needle 21 is formed about a chaining finger 162 on needle plate 18 and a stub finger 150 on the presser foot assembly.

From FIGS. 5 and 6, it is believed apparent that two chaining fingers could readily be employed on the needle plate 18, with the two stub fabric support fingers being carried on the presser foot. Similarly, it is believed apparent that the needle plate could be constructed with a chaining finger in the position of the stub finger 60 and a stub fabric support finger in the position of the chaining finger 162, with a stub fabric supporting finger on the presser foot in the location of the chaining finger 48 and a chaining finger on the presser foot in the location of the stub fabric support finger 150. Thus, while both of these further combinations are useful, and may have advantages in certain sewing operations over the embodiments illustrated, it is not believed necessary to illustrate these specific embodiments in the drawings.

Referring now to FIGS. 7-10, operation of the invention is illustrated in an overseaming machine configuration in which the length of the individual stitches is relatively long in comparison with the spacing ofthe needles 20, 21. The length L of the individual stitches is, of course, determined by the distance the workpiece 15 is advanced by the feed mechanism 14 during each feeding movement. In FIGS. 79, the needle spacing is illustrated as being 1% L so that stitches formed by needle 21 are spaced exactly half way between the stitches formed by needle 20.

As illustrated in FIG. 7, when the needles 20, 21 penetrate the workpiece 15, lower loopers 23, 24 pick a loop of threads 31, 33, respectively, beneath the needle plate 18. As the needles are retracted, as shown in FIG. 8, the loops of thread are held beneath the workpiece and led laterally into the machine where they are passed to the upper loopers 27, 28. Movement of the needles to the rear of the machine during retraction leads the threads 31, 33 rearward from the point of penetration. As the needles are being retracted, the feed mechanism shifts the workpiece to the rear, thereby shifting the anchored end of the threads rearwardly a distance equal to the length of one stitch. As the needles start their descent to again penetrate the workpiece, the upper loopers pass the loops of thread above the workpiece across the path of the needles as shown in FIG. 10. Where the increment of feed is large relative to the needle spacing, the forward needle thread 33 will engage the arm 52 and be held out of the path of movement of the rear upper looper 27 as indicated in FIG. 9.

Since arm 52 is spaced above the bottom surface of presser foot 32, it will not interfere with the stitches being cast off the forward chaining finger 48. Thus, this arm 52 may be positioned on the presser foot at any point necessary to hold the forward needle thread out of the path of the rear upper looper. Alternatively, the arm may be provided with a forwardly directed enlargement, or thread guide, to lead the forward thread as far forward as desired, the only limit being that adequate clearance be left for the forward needle.

While arm 52 is illustrated as acting both as a thread guide and as a support for the stub finger 150 or the chaining finger 50, it is believed apparent that the arm would be equally effective as a thread guide without the use of these fingers as when employed with a machine having two chaining fingers on the needle-plate as described above.

Referring now to the embodiment illustrated in FIGS. 11 and 12, it is seen that the invention is not limited to machine configurations employing only two needles. In this embodiment, sometimes referred to as a dual tandem arrangement, two sets of needles 120, 121 and 120a, 1210 are mounted in side-byside relation with the needles of each set being aligned in the direction of feed of the work material through the machine. The needle plate 118 includes an elongated chaining finger 160 formed on and projecting rearwardly from a laterally extending arm 162. A second elongated chaining finger 164 is positioned between finger 160 and the body of the needle plate. Chaining finger 164 is the cantilevered end of an elongated bar 166 retained in a slot 167 in the top surface of needle plate 118 by a pin 168 in a manner similar to that illustrated in US Pat. No. 3,100,469.

The presser foot 132 supports a second pair of chaining fingers 150, 151 positioned in alignment with and to the rear of fingers 160, 164. Chaining fingers 150, 151 are supported at their forward end by a thread guide and support arm member 152 which, in turn, is supported on a bracket 154 on foot 132 by nut 156. The chaining fingers 160, 164 are somewhat longer than those illustrated in the previously described embodiments, preferably extending slightly beneath the forward portions of fingers 150, 151 so that a workpiece is supported thereby adjacent to the point of penetration by the rear needles. Alternatively, stub fingers such as those described above could be employed.

It is pointed out that stitches formed by needle are cast around chaining finger whereas those formed by needle 120a are cast around chaining fingers 160 and 164. Similarly,

stitches formed by needle 12! are only cast around chaining finger 150 while those formed by needle 121a are cast around both fingers 150 and 151.

From the above, it is believed apparent that l have provided an overedge sewing machine of the type employing a pair of needles aligned in the direction of stitch formation with an improved chaining mechanism which serves to provide an equal cross section chain forming structure at each stitch forming station to allow individual stitches simultaneously formed to be shed from the forming fingers simultaneously. Thus, comparable stitches can be formed with the two needles so that a seam formed on the machine gives the appearance of a seam formed from a single thread. While I have disclosed and described preferred embodiments of my invention, i wish it understood that I do not intend to be limited thereto, but that I do intend to include all embodiments which would be apparent to one skilled in the art and which come within the spirit and scope of my invention.

lclaim:

t. In an overedge sewing machine having a pair of needles supported in alignment in the direction of feed ofa workpiece through the machine and means for driving said pair of needles to simultaneously penetrate the workpiece at spaced points along the length of a seam formed by the machine, the improvement comprising, a pair of chaining fingers, support means mounting said chaining fingers in alignment in said direction of feed and in laterally spaced relation to said needles as said needles penetrate a workpiece, a pair of stub fabric support fingers, and means supporting said stub fabric supporting fingers in vertically opposed relation to said chaining fingers whereby the edge of a piece of work material being sewn on said machine will be supported between said chaining fingers and the opposed stub fabric supporting fingers in the area adjacent said needles as said needles penetrate the work material.

2. In an overedge sewing machine according to claim 1, the further improvement wherein said chaining fingers are of substantially the same cross-sectional area at points adjacent said needles.

3. In an overedge sewing machine according to claim 2, the further improvement wherein said pair of chaining fingers are of substantially the same length from said points adjacent said needles to their rear end.

4. in an overedge sewing machine according to claim 1, the further improvement comprising thread guide means mounted above said chaining fingers and extending transversely of said direction of feed between said needles when said needles penetrate a workpiece, said thread guide being operable to engage a length of thread extending between the workpiece and the front needle to deflect the thread from the path of the rear upper looper of the machine.

5. ln an overedge sewing machine having a pair of needles supported in alignment in the direction of feed ofa workpiece through the machine and means for driving said pair of needles to simultaneously penetrate a workpiece at spaced points along the length of a seam formed by the machine, the improvement comprising, a presser foot, a pair of arms mounted on and projecting laterally from one side edge of said presser foot, a pair of chaining fingers each having a base portion supported on one of said arms, said arms being spaced from one another and supporting said chaining fingers in alignment in said direction of feed and in laterally spaced relation to said needles whereby independent stitches formed with respective threads carried by said needles are formed around separate chaining fingers.

6. in an overedge sewing machine as defined in claim 5, the further improvement comprising a needle plate, and a pair of fabric supporting fingers mounted on said needle plate and positioned one beneath each of said chaining fingers.

7. In an overedge sewing machine having a pair of needles supported in alignment in the direction of feed ofa workpiece through the machine and means for driving said pair of needles to simultaneously penetrate a workpiece at spaced points along the length of a seam formed by the machine, the improvement comprising, a needle plate, a pair of arms formed on and projecting laterally from one side edge of said needle plate in spaced relation to one another in said direction of feed, a pair of chaining fingers each having a base portion mounted on one of said arms, said chaining fingers extending rearward from said arms in alignment in said direction of feed and in laterally spaced relation to said needles, a presser foot, a pair of arms mounted on and extending laterally from one side edge of said presser foot in vertically spaced relation to said arms on said needle plate, and a pair of fabric supporting fingers mounted one on each of said arms on said presser foot.

8. In an overedge sewing machine having a pair of needles supported in alignment in the direction of feed ofa workpiece through the machine and means for driving said pair of needles to simultaneously penetrate a workpiece at spaced points along the length of a seam formed by the machine, the improvement comprising a needle plate, a first arm supported on and projecting laterally from one side edge of said needle plate, a presser foot, a second arm supported on and projecting laterally from one side edge of said presser foot, said first and second arms being spaced from one another along said direction of feed, and a pair of chaining fingers mounted one on each of said arms and extending rearwardly therefrom in alignment in said direction of feed and in laterally spaced relation to said needles.

9. In an overedge sewing machine as defined in claim 8, the further improvement comprising a second pair ofchaining fingers mounted one on each of said arms and extending rearwardly therefrom in alignment in said direction of feed and in laterally spaced relation to said first pair of chaining fingers.

10. In an overedge sewing machine as defined in claim 8, the further improvement comprising a pair of fabric support fingers mounted one on said presser foot and positioned in vertically opposed relation to said chaining finger on said first arm and the other on said needle plate in vertically opposed relation to said chaining finger on said second arm.

11. In an overedge sewing machine having a pair of needles supported in alignment in the direction of feed ofa workpiece through the machine and means for driving said pair of needles to simultaneously penetrate a workpiece at spaced points along the length of a seam formed by the machine, the improvement comprising a pair of chaining fingers, support means mounting said chaining fingers in alignment in said direction of feed and in laterally spaced relation to said needles as said needles penetrate a workpiece whereby independent stitches formed with respective threads carried by said needles are formed around separate chaining fingers, thread guide means, and mounting means supporting said thread guide means above said chaining fingers and extending transversely of said direction of feed between said needles when said needles penetrate a workpiece, said thread guide being operable to engage a length of thread extending between the workpiece and the front needle to deflect the length of thread from the path of the rear upper looper of the machine.

12. in an overedge sewing machine according to claim 11, the further improvement wherein said mounting means comprises a presser foot, and a mounting bracket on said presser foot, said thread guide comprising an arm mounted on said bracket and projecting laterally from one side edge of said presser foot.

13. For use in an overedge sewing machine having a pair of needles supported in alignment in the direction of feed of a workpiece through the machine and means for driving said pair of needles to simultaneously penetrate the workpiece at spaced points along the length of a seam formed by the machine, a presser foot comprising, a substantially flat body portion, a front and a rear laterally extending arm mounted on and projecting outward from one side edge of said body portion, said arms being spaced from one another in the direction of feed of a workpiece through the machine, a first chaining finger supported at its base on said front arm and extending therefrom toward said rear arm and in laterally spaced rela tion to said one side edge to define a first needle opening in said presser foot, and a second chaining finger supported at its base on said rear arm and extending therefrom in laterally spaced relation to said one edge and in a direction away from said first chaining finger to define a second needle opening in said presser foot, said first and said second needle openings being aligned in the direction of feed of aworkpiece through the machine and being positioned so that one of the needles passes through each of said needle openings when the needles penetrate a workpiece.

14. In an overedge sewing machine having a pair of needles supported in alignment in the direction of feed ofa workpiece through the machine and means for driving said pair of needles to simultaneously penetrate a workpiece at spaced points along the length of a seam formed by the machine, the improvement comprising thread guide means, and mounting means supporting said thread guide means in position extending transversely of said direction of feed and projecting between said needles when said needles penetrate a workpiece, said thread guide being operable to engage a length of thread extending between the workpiece and the front needle to deflect the length of thread from the path of the rear upper looper of the machine.

15. In an overedge sewing machine according to claim 14, the further improvement wherein said mounting means comprises a presser foot, and a mounting bracket on said presser foot, said thread guide comprising an arm mounted on said bracket and projecting laterally from one side edge of said presser foot.

16. In an overedge sewing machine having a first pair of needles supported in alignment in the direction of feed of a workpiece through the machine, a second pair of needles aligned in said direction of feed and positioned in laterally spaced relation to said first pair of needles, and means for driving said first and said second pair of needles to simultane ously penetrate a workpiece at spaced points along a seam formed by said machine, the improvement comprising, a needle plate, a first pair of chaining fingers mounted on said needle plate in laterally spaced relation to one another and extending one adjacent each of the forward needles of said pairs of needles and on corresponding sides thereof, a presser foot, a second pair of chaining fingers mounted on said presser foot in laterally spaced relation to one another and in alignment one with each of said first pair of chaining fingers. 

1. In an overedge sewing machine having a pair of needles supported in alignment in the direction of feed of a workpiece through the machine and means for driving said pair of needles to simultaneously penetrate the workpiece at spaced points along the length of a seam formed by the machine, the improvement comprising, a pair of chaining fingers, support means mounting said chaining fingers in alignment in said direction of feed and in laterally spaced relation to said needles as said needles penetrate a workpiece, a pair of stub fabric support fingers, and means supporting said stub fabric supporting fingers in vertically opposed relation to said chaining fingers whereby the edge of a piece of work material being sewn on said machine will be supported between said chaining fingers and the opposed stub fabric supporting fingers in the area adjacent said needles as said needles penetrate the work material.
 2. In an overedge sewing machine according to claim 1, the further improvement wherein said chaining fingers are of substantially the same cross-sectional area at points adjacent said needles.
 3. In an overedge sewing machine according to claim 2, the further improvement wherein said pair of chaining fingers are of substantially the same length from said points adjacent said needles to their rear end.
 4. In an overedge sewing machine according to claim 1, the further improvement comprising thread guide means mounted above said chaining fingers and extending transversely of said direction of feed between said needles when said needles penetrate a wOrkpiece, said thread guide being operable to engage a length of thread extending between the workpiece and the front needle to deflect the thread from the path of the rear upper looper of the machine.
 5. In an overedge sewing machine having a pair of needles supported in alignment in the direction of feed of a workpiece through the machine and means for driving said pair of needles to simultaneously penetrate a workpiece at spaced points along the length of a seam formed by the machine, the improvement comprising, a presser foot, a pair of arms mounted on and projecting laterally from one side edge of said presser foot, a pair of chaining fingers each having a base portion supported on one of said arms, said arms being spaced from one another and supporting said chaining fingers in alignment in said direction of feed and in laterally spaced relation to said needles whereby independent stitches formed with respective threads carried by said needles are formed around separate chaining fingers.
 6. In an overedge sewing machine as defined in claim 5, the further improvement comprising a needle plate, and a pair of fabric supporting fingers mounted on said needle plate and positioned one beneath each of said chaining fingers.
 7. In an overedge sewing machine having a pair of needles supported in alignment in the direction of feed of a workpiece through the machine and means for driving said pair of needles to simultaneously penetrate a workpiece at spaced points along the length of a seam formed by the machine, the improvement comprising, a needle plate, a pair of arms formed on and projecting laterally from one side edge of said needle plate in spaced relation to one another in said direction of feed, a pair of chaining fingers each having a base portion mounted on one of said arms, said chaining fingers extending rearward from said arms in alignment in said direction of feed and in laterally spaced relation to said needles, a presser foot, a pair of arms mounted on and extending laterally from one side edge of said presser foot in vertically spaced relation to said arms on said needle plate, and a pair of fabric supporting fingers mounted one on each of said arms on said presser foot.
 8. In an overedge sewing machine having a pair of needles supported in alignment in the direction of feed of a workpiece through the machine and means for driving said pair of needles to simultaneously penetrate a workpiece at spaced points along the length of a seam formed by the machine, the improvement comprising a needle plate, a first arm supported on and projecting laterally from one side edge of said needle plate, a presser foot, a second arm supported on and projecting laterally from one side edge of said presser foot, said first and second arms being spaced from one another along said direction of feed, and a pair of chaining fingers mounted one on each of said arms and extending rearwardly therefrom in alignment in said direction of feed and in laterally spaced relation to said needles.
 9. In an overedge sewing machine as defined in claim 8, the further improvement comprising a second pair of chaining fingers mounted one on each of said arms and extending rearwardly therefrom in alignment in said direction of feed and in laterally spaced relation to said first pair of chaining fingers.
 10. In an overedge sewing machine as defined in claim 8, the further improvement comprising a pair of fabric support fingers mounted one on said presser foot and positioned in vertically opposed relation to said chaining finger on said first arm and the other on said needle plate in vertically opposed relation to said chaining finger on said second arm.
 11. In an overedge sewing machine having a pair of needles supported in alignment in the direction of feed of a workpiece through the machine and means for driving said pair of needles to simultaneously penetrate a workpiece at spaced points along the length of a seam formed by the machine, the improvement comprising a pair of chaining fingerS, support means mounting said chaining fingers in alignment in said direction of feed and in laterally spaced relation to said needles as said needles penetrate a workpiece whereby independent stitches formed with respective threads carried by said needles are formed around separate chaining fingers, thread guide means, and mounting means supporting said thread guide means above said chaining fingers and extending transversely of said direction of feed between said needles when said needles penetrate a workpiece, said thread guide being operable to engage a length of thread extending between the workpiece and the front needle to deflect the length of thread from the path of the rear upper looper of the machine.
 12. In an overedge sewing machine according to claim 11, the further improvement wherein said mounting means comprises a presser foot, and a mounting bracket on said presser foot, said thread guide comprising an arm mounted on said bracket and projecting laterally from one side edge of said presser foot.
 13. For use in an overedge sewing machine having a pair of needles supported in alignment in the direction of feed of a workpiece through the machine and means for driving said pair of needles to simultaneously penetrate the workpiece at spaced points along the length of a seam formed by the machine, a presser foot comprising, a substantially flat body portion, a front and a rear laterally extending arm mounted on and projecting outward from one side edge of said body portion, said arms being spaced from one another in the direction of feed of a workpiece through the machine, a first chaining finger supported at its base on said front arm and extending therefrom toward said rear arm and in laterally spaced relation to said one side edge to define a first needle opening in said presser foot, and a second chaining finger supported at its base on said rear arm and extending therefrom in laterally spaced relation to said one edge and in a direction away from said first chaining finger to define a second needle opening in said presser foot, said first and said second needle openings being aligned in the direction of feed of a workpiece through the machine and being positioned so that one of the needles passes through each of said needle openings when the needles penetrate a workpiece.
 14. In an overedge sewing machine having a pair of needles supported in alignment in the direction of feed of a workpiece through the machine and means for driving said pair of needles to simultaneously penetrate a workpiece at spaced points along the length of a seam formed by the machine, the improvement comprising thread guide means, and mounting means supporting said thread guide means in position extending transversely of said direction of feed and projecting between said needles when said needles penetrate a workpiece, said thread guide being operable to engage a length of thread extending between the workpiece and the front needle to deflect the length of thread from the path of the rear upper looper of the machine.
 15. In an overedge sewing machine according to claim 14, the further improvement wherein said mounting means comprises a presser foot, and a mounting bracket on said presser foot, said thread guide comprising an arm mounted on said bracket and projecting laterally from one side edge of said presser foot.
 16. In an overedge sewing machine having a first pair of needles supported in alignment in the direction of feed of a workpiece through the machine, a second pair of needles aligned in said direction of feed and positioned in laterally spaced relation to said first pair of needles, and means for driving said first and said second pair of needles to simultaneously penetrate a workpiece at spaced points along a seam formed by said machine, the improvement comprising, a needle plate, a first pair of chaining fingers mounted on said needle plate in laterally spaced relation to one another and extending one adjacent each of the forward needles of said pairs of needles aNd on corresponding sides thereof, a presser foot, a second pair of chaining fingers mounted on said presser foot in laterally spaced relation to one another and in alignment one with each of said first pair of chaining fingers. 